<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>关注微信公众号</title>
    <link rel="stylesheet" href="css/style.css">
    <script src="js/public.js"></script>
</head>
<body>
    <div class="step">
        <img src="image/getcode.png" >
    </div>
    <div class="verify">
        <div class="import">
            <input name="txtCode" type="text" id="txtCode" placeholder="请输入验证码" class="input">
        </div>
        <input type="submit" name="btnSubmit" value="" id="btnSubmit" class="subBefore">
       <p id="divMsg" class="CheckCodemsg"></p>
    </div>
</body>
<script>
    var oInp = document.querySelector('.input');
    var oSub = document.getElementById('submit');
    oInp.oninput = function(){
        if(oInp.value.length == 0){
            oSub.className = 'subBefore';
        } else{
            oSub.className = 'subHover';
        } 
    }
    
</script>
</html>